Sealing means for fluid operated pump system



May 11, 1965 R. F. MGARTHUR ETAL SEALING MEANS -FOR FLUID OPERATED PUMP SYSTEM Original Filed June 8, 1959 4 Sheets-Sheet 1 May ll, 1965 R. F. IMGARTHUR ETAL SEALING MEANS FOR FLUID OPERATED PUMP SYSTEM Original Filed June 8, 1959 4 Sheets-Sheet 2 (192,16: g. ff@ 40 :P5 0 $.PvE www n .mms Mm W i., ,mw mm n l y MH:

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SEALING' MEANS lFOR FLUID OPERATED PUMP SYSTEM Original Filed June 8', 1959 4 Sheets-Sheet 3 rv w 4mm w m u /////////////////7// ////////////////////f/ I I C 2 #7,15/ Mfwf l i -l o Nxxk 4 a J am I w Ir j i; IL a r u y w w a Mp7 f a Many 11, 1965 R. F. MGARTHUR ETAL I SELING MEANSA FOR FLUID OPERATED PUMP SYSTEM 4 Sheets-Sheet 4 Original Filed June 8, 1959 llllnlll Y im v 1141.

United States Patent O 3,182,598 SEALING MEANS FOR FLUID OPERATED PUMP SYSTEM Ralph F. McArthur, Huntington Park, and Mathew R. Mecusker, La Habra, Calif., assignors to Kobe, Inc., Huntington Park, Calif., a corporation of California Original application .lune 8, 1959, Ser. No. 818,870, now Patent No. 3,078,804, dated Feb. 26, 1963. Divided and this application Aug. 3, 1962, Ser. No. 214,635 4 Claims. (Cl. 10S-46) This application is a division of our co-pending application Serial No. 818,870, tiled June 8, 1959, now Patent No. 3,078,804, issued February 26, 1963.

The present invention relates to a fluid-operated oilwell pump system comprising a .bottom hole assembly or housing adapted to receive therein an elongated, fluid operated pump assembly of the reciprocating type having an engine or motor means which is actuab-le by an operating fluid, such as oil, under high pressure to operate a pump means for pumping production fluid to the surface.

In such a fluid operated pump sys-tem, the pump assembly carries external sealing means engageable with the bottom hole assembly for preventing intermingling of such fluids as the operating fluid under pressure for actuating the motor means, the spent operating fluid discharged by the motor means, the production fluid from the well admitted to the pump means, and the production iluid discharged by the pump means.

An important object of the invention is to provide a pump assembly having thereon external sealing means engageable with the bottom hole assembly and including elastomeric annular seals which are constantly in states of compression when the pump assembly is in its operative position.

Another object is to provide a pump assembly wherein each elastomeric annular seal is maintained in a state of compression by constantly applying thereto a pressure force which produces a pressure within the seal greater than any iluctuating fluid pressure differential :to which it may be subjected during operation of the pump assembly.

Wi-th the foregoing construction, the elastomeric annular seals are prevented from expanding and contracting excessively in response to the application of lluctuating iluid pressure `force differentials thereto during the operation of the pump assembly, thereby minimizing internal friction vthin the seals and thereby preventing the detrimental heat genera-tion which would otherwise result.

A further object of the invention is to provide means for loading each elastomeric annular seal which comprises a differential-area sleeve engageable with the seal and exposed to suitable iluid pressures associated with the pump assembly.

Still another object of the invention is to provide a bottom hole housing incorporating means for [facilitating the assembly of various components thereof in their proper relative positions to properly accommodate the pump assembly.

The foregoing objects, advantages, feature-s and results of the present invention, together with various other objects, advantages, features and results thereof which will be eviden-t to those skilled in the fluid operated pump art, may be achieved with the exemplary embodiments -of the invention described in detail hereinafter and illustrated in the accompanying drawings, in which:

FIG. 1 is a vertical sectional view illustra-ting diagrammatically a fluid operated pump system which embodies the invention as installed in a well, this pump system being illustrated in speciiic detail throughout the remainder of the drawings;

FIG. 2 is a vertical sectional view of the upper end of the fluid operated pump system of the invention shown in specic detail, and is taken as indicated by the arro-wed line 2-2 of FIG. 7;

FIG. 3 is a vertical sectional view of a portion of the pump system below that illustrated in FIG. 2 and is taken along the arrowed line 3-3 of FIG. 8;

FIG. 4 is a vertical sectional view of a portion of the pump system below that illustrated in FIG. 3 and is taken as indicated by the arrowed line 4*-4 of FIG. 9;

FIG. 5 is a vertical sectional view of a portion of the pump system below that of FIG. 4;

FIG. 6 is a vertical sectional view of the lower end of the pump system; f

FIGS. 7, 8 and 9 are horizontal sectional views respectively taken along the arrowed lines 7-7, 8-8 and 9 9 of FIGS. 2, 3 and 4, respectively; and

FIGS. 10 and ll are enlarged, fragmentary vertical section-al views illustrating seal loading means of the nvention in more detail.

Referring particularly to FIG. 1 `of the drawings, the fluid operated pump system of the invention includes a bottom hole assembly 2li which provides a housing means for receiving and housing in an operative position therein a free, fluid operated pump assembly 22. The bottom hole assembly 20 is suspended in a Well casing 24 provided at its lower end with a perforated linerV 26, shown as integral with the casing, through which production fluid from a surrounding productive formation 28 may enter the well. The suspension means for the bottom hole assembly 20 comprises a tubing system which includes a pump tubing Sil that Iacts as a supply tubing for delivering an operating fluid under pressure to the pump assembly 22 when it is in its operative position in the bottom hole assembly, ,a return tubing 32 for conveying spent operating fluid from the pump `assembly to the surface, and a production tubing 34 `for conveying to the surface production iluid from the well which is discharged by the rpump assembly. The free pump assembly 22 is hydraulically movable fbetween its operative position in the bottom hole assembly 20 and the surface through the supply tubing 30 in the construction illustrated.

It will be understood that while a separate return tubing 32 for the spent operating iluid has been disclosed, thereby providing a closed operating fluid system, the spent operating fluid may be mixed with the production iluid and returned via the production tubing 34, thereby providing an open operating tluid system.

Considering the bottom hole assembly 20 in a general way, and primarily with reference to FIG. 1 of the drawings, it includes an upper sealing collar 36 to which the lower ends of the supply and return tubings 30 and 32 are connected. As will be described in more detail hereinafter, the upper sealing collar 36 provides an operating iluid exhaust passage means 38 which conveys spent operating fluid from the pump assembly 22 to the return tubing 32.

Connected to the lower end of the upper sealing collar 36 is the upper end of a motor housing tube 40 to the lower end of which is connected an upper intermediate sealing collar 42. The lower end of the production tubing 34 is connected to the sealing collar 42 and this sealing collar is provided with a branch outlet passage means 44 which conveys production fluid discharged by the pump assembly 22 to a main outlet passage means 46 for production iluid which leads to the lower end of the production tubing 34.

Connected to the lower end of the upper intermediate sealing collar 42 is the upper end of an upper pump housing tube 48 to the lower end of which is connected a lower intermediate sealing collar 50 having therein a branch outlet passage means 52 which conveys production fluid discharged by the pump assembly 22 to the main outlet passage means 46.

The lower end of the lower intermediate sealing collar 50 has connected thereto the upper end of a lower pump housing tube 54 and connected to the lower end of this tube is a lower sealing collar 55 havin`g a bottom shoe 56 connected thereto. Formed in the bottom shoe 56 is a branch outlet passage means 58 which conveys production lluid discharged by the pump assembly 22 to the main outlet passage means 46.

The supply tubing 30, the sealing collars 36, 42, 50 and 55, the motor housing tube 40, the pump housing tubes 48 and 54, and the bottom shoe 56 are all axially, i.e., vertically, aligned and provide a housing or housing means for the pump assembly 22, the latter being movable between the surface and an operative position within the bottom hole assembly through the supply tubing. The bottom shoe 56 is provided therein with an annular seat 60 for a standing valve assembly 62 on which the lower end of the pump assembly 22 is seated when the pump assembly is in its operative position in the bottom hole assembly.

The standing valve assembly communicates with the interior of the perforated liner 26 and constitutes the lower end of a production fluid inlet passage means 64 for conveying production liuid from the well to the pump assembly 22 for pumping into the main outlet passage means 46 by way of the branch outlet passage means 44, 52 and 58. The inlet passage means 64 includes, generally, an inlet passage 66 formed in an inlet plug 68 and a lower sealing adapter 154 of the pump assembly 22, the inlet plug forming the lower end of the pump assembly and being seated on the standing valve assembly 62 when the pump assembly is in its operative position in the bottom hole assembly 20. The inlet passage means 64 also includes a lower annular passage 70 the lower end of which communicates with the inlet passage 66, the lower annular passage 70 having outer and inner walls respectively formed by the bottom hole and pump assemblies 20 and 22 and extending from within the sealing collar 5S upwardly through the lower pump housing tube 54 into the lower intermediate sealing collar 50. The inlet passage means 64 further includes an upper annular passage 72 the lower end of which is connected to the upper end of the lower annular passage 70 by a bypass passage 74 formed in the lower intermediate sealing collar 50, the upper annular passage 72 having outer and inner walls respectively formed by the bottom hole and pump assemblies 20 and 22 and extending upwardly from within the lower intermediate sealing collar 50 through the upper pump housing tube 48 into the upper intermediate sealing collar 42.

In will be noted that, with the exception of the inlet passage 66 of the inlet passage means 64, all of the components or portions of the production iluid inlet passage means 64 and the production lluid outlet passage means 44, 46, 52 and 58 are located within the bottom hole assembly 20 externally of the pump assembly 22 so that they do not occupy any space within the pump assembly which would tend to reduce the displacement thereof. Since the inlet passage 66 is formed in the inlet plug 68 at the lower end of the pump assembly 22, it has no effect on the displacement of the pump assembly.

Similar considerations are applicable to the handling of the operating iluid under pressure for actuating the pump assembly 22 and the spent operating lluid discharged by the pump assembly, the high pressure operating lluid and the low pressure spent operating lluid being handled in passages Within the bottom hole assembly 20 externally of the pump assembly 22 wherever necessary to avoid a tendency to reduce the displacement of the pump assembly with respect to the operating fluid. In this connection, it will be noted that the operating fluid exhaust passage means 38 is formed in the upper sealing collar 36 externally of the pump assembly 22. With this same objective in mind, the bottom hole assembly 20 provides an annular operating lluid passage 76 which extends from within the upper sealing collar 36 downwardly through the motor housing tube 40 into the upper intermediate sealing collar 42, the outer and inner Walls of this annular passage also being formed by the bottom hole and pump assemblies 20 and 22, respectively, so that such passage is also located entirely externally of the pump assembly. The function of the annular operating fluid passage 76 will be brought out hereinafter.

Considering the pump assembly 22 in detail now, it includes at its upper end a packer nose assembly 78 comprising a tubular packer mandrel 80 having thereon down- Wardly facing packer cups 82 which make fluid tight seals with the supply tubing 30 when lluid pressure is applied therebeneath, whereby the pump assembly may be moved upwardly through the supply tubing to the surface hydraulically in a manner to be described. The packer mandrel 80 is provided therein with ports forming an operating lluid intake 84 for admitting operating lluid under pressure from the supply tubing 30 into the pump assembly 22.

The lower end ol' the packer mandrel 80 is connected to an upper sealing adapter 86 which registers with the upper sealing collar 36 when the pump assembly 22 is in its operative position. The upper sealing adapter 86 is provided therein with ports forming an operating fluid exhaust 88 which communicates with the exhaust passage means 38 in the upper sealing collar 36 when the pump assembly 22 is in its operative position. The operating iuid exhaust 88 and the exhaust passage means 38 are isolated by elastomeric annular seals 90 and 92 carried by the upper sealing adapter 86 respectively above and below the operating iluid exhaust S8 and engageable with the upper sealing collar 36.

Connected to the lower end of the upper sealing adapter 86 is a lluid operated engine or motor section 94 of the pump assembly 22, the lower end of the motor section being connected to an upper intermediate sealing adapter 96 which is disposed within the upper intermediate sealing collar 42 when the pump assembly 22 is in its operative position. The annular operating lluid passage 76 within the motor housing tube 40 encircles the motor section 94 of the pump assembly 22 and is isolated by the seal 92 on the upper sealing adapter 86 and by an elastomeric annular seal 98 on the sealing adapter 96 and engageable with the sealing collar 42.

The lluid operated motor section 94 of the pump assembly 22 includes a motor cylinder 100 formed by a motor cylinder barrel or tube 101 and having therein a motor piston 102 which is reciprocated in the motor cylinder by connecting the upper and lower ends of the motor cylinder rst to the operating lluid intake and exhaust 84 and 88, respectively, and then to the operating uid exhaust and intake 88 and 84, respectively, in an alternating manner. In other words, the connections between the upper and lower ends of the motor cylinder and the operating fluid intake and exhaust 84 and 88 lare alternately reversed. thereby applying to the motor piston 102 an alternating fluid pressure force differential which reciprocates it in its cylinder.

The foregoing effect is Iachieved by an engine or motor valve 104, FIG. 2, forming part of the motor section 94 of the pump assembly 22 and communicating with the operating lluid intake and exhaust 84 and 8S. The engine valve 104 is conventional and may, for example, be of the type disclosed in Patent No. 2,311,157, granted February 16, 1943 to Clarence J. Coberly. Consequently, it is unnecessary to consider the engine valve 104 in detail herein, it being sutlicient to point out that it includes a fluid operated valve member 106 slidable vertically in a valve body 108 and controlled by a valve rod 110 connected to the motor piston 102. The valve body 108 connects the upper end of the motor cylinder barrel 101 to the upper sealing adapter 86 as shown in sage 76 communicates with ports FIG. 2, the lower end of the motor cylinder barrel being connected to the upper intermediate sealing adapter 96, as shown in FIG. 3.

The motor section 94 of the pump assembly 22 is provided with two operating lluid passage means 112 and 114 respective-ly connecting `the engine valve 104 to the upper and lower ends of the motor cylinder 100, the two passage means mentioned providing the communication between the engine valve and the upper and lower ends of the motor cylinder which is necessary to permit the engine valve to apply to the motor piston 102 the alternating fluid pressure force differential discussed previously. As shown in FIG. 2, the operating fluid passage means 112 establishing communication between the engine valve 104 and the upper end of the motor cylinder 100 includes suitable passages, ports and the like in the engine valve body 108 and in a tubular fitting assembly 116 disposed in the upper end of the motor cylinder barrel 101 adjacent the engine valve 104. The passages, ports and the like forming the operating fluid passage means 112 are clearly shown in FIG. 2 of the drawings and it is therefore thought unnecessary to describe them in detail.

The operating fluid passage means 114 connecting the engine valve 104 to the lower end of the motor cylinder 100 includes the annular operating Huid passage 76 described previously. The upper end of the annular pas- 118 which, in turn, communicate with the engine valve 104 through suitable passages, ports, and the I'like formed in the fitting assembly 116 and the engine valve body 108 and adequately illustrated in FIG. 2 of the drawings so that describing them in detail is unnecessary. The ports 118 are formed in the upper end of the barrel or tube 101 forming the motor cylinder 100 and are prevented from communicating with the upper end of the motor cylinder proper by the fitting assembly 116. The lower end of the annular passage 76 communicates with ports 120 formed in the lower end of the barrel 101 and communicating with the lower end of the motor cylinder 100 below the motor piston 102 -through suitable ports, passages, and the like formed in the upper intermediate sealing adapter 96 and clearly illustrated in FIG. 3 of the drawings.

The pump means of the pump assembly 22 includes in the construction illustrated upper and lower doubleacting pump sections 122 and 124 respectively disposed in the upper and lower pump housing tubes 48 and 54 when the pump assembly 22 is in its operative position. The upper and lower pump sections 122 and 124 respectively include upper and lower pump cylinders 126 and 128 respectively formed by upper and lower pump cylinder barrels or tubes 130 and 132. Respectively reciprocable in the upper and lower pump cylinders 126 and 128 are upper and lower pump pistons 134 and 136, the upper pump piston 134 being connected to the motor piston 102 by a rod 138, FIGS. 3 and 4, and the two pump pistons being interconnected by a rod 140, FIGS. 4 and 5. Connected to the lower pump piston 136 and extending downwardly therebelow into a balance tube 142, FIGS. 5 and 6, is a lower rod 144. The cross sectional area of the lower rod 144 is the same as that of the valve rod 110, and the rods 110, 138, 140 and 144 and the pistons 102, 134 and 136 are all tubular so that the fluid pressure acting downwardly on the valve rod is also present in the balance tube 142 to act upwardly on the lower rod 144. Thus, the

piston and rod assembly is hydraulically balanced with respect to the fluid pressure acting downwardly on the Valve rod 110, which Iiuid pressure is the operating uid pressure in the supply tubing 30, being applied to the upper end of the valve rod 110 through the packer mandrel 80, an axial passage 146, FIG. 2, in the upper sealing adapter 86 and the interior of the engine valve member 106.

Considering the pump means of the pump assembly 22 in more detail, the upper pump cylinder barrel 130 is `in FIG. 4 of the drawings.

6 connected to the lower end of the upper intermediate sealing adapter 96, FIG. 3, and the lower end of this barrel is connected to the upper end of a lower intermediate sealing adapter 148, FIG. 4. The upper end of the lower pump cylinder barrel 132 is connected to the lower end of the lower intermediate sealing adapter 148, FIG. 4, and

the lower end of the lower pump cylinder barrel is connected to a fitting 150, as shown in FIG. 5. The balance tube 142 mentioned previously is connected to the lower end of the fitting and a barrel or tube 152 surrounding the balance tube 142 connects the tting 150 to the lower sealing adapter 154, which is disposed within the lower sealing collar 55 when the pump assembly 22 is in its operative position. The inlet plug 68 at the lower end of the pump assembly is connected to the lower sealing adapter 154.

Since the upper and lower pump sections 122 and 124 are double acting as previously stated, each is provided with two vertically spaced production fluid inlets. The upper and lower production iiuid inlets of the upper pump section 122 are designated by the numerals 156 and 158, respectively, and the upper and lower production iiuid inlets of the lower pump section 124 are designated by the numerals and 162, respectively. The production fluid inlets 156 and 158 for the upper pump section 122 communicate with the upper annular passage 72 of the production fluid inlet passage means 64, while the production fiuid inlets 160 and 162 of the lower pump section 124 communicate with the lower annular passage 70 of the production fluid inlet passage means 64.

The upper annular production inlet passage 72 is isolated, so that it communicates only with that portion of the exterior of the upper pump section 122 having the production iiuid inlets 156 and 158 therein, by elastomeric annular seals 164 and 166 respectively carried by the upper and lower intermediate sealing adapters 96 and 148. Similarly, the lower annular production fluid inlet passage 70 is isolated, so that it communicates only with that portion of the exterior of the lower pump section 124 having the production fluid inlets 160 and 162 therein, by elastomeric annular seals 168 and 170 respectively carried by the lower intermediate and the lower` sealing adapters 148 and 154.

As shown in FIG. 3, the upper production fluid inlet 156 of the upper pump section 122, which inlet is shown as comprising circumferentially spaced ports, is formed in the upper end of the upper pump cylinder barrel 130 and communicates with the upper end of the upper pump cylinder 126 through a suitable inlet check valve means 172 carried by the upper intermediate sealing adapter 96. The inlet check valve means 172 includes 4suitable passages, ports, and the like in the upper intermediate sealing adapter 96 which it is thought unnecessary to describe specifically, these being clearly shown in FIG. 3 of the drawings. Similarly, the lower production fluid inlet 158 of the upper pump section 122 is formed in the lower end of the upper pump cylinder barrel 130 and communicates with the lower end of the upper pump cylinder 126 through a suitable inlet check valve means 174 carried by the lower intermediate sealing adapter 148, as shown Again similarly, the upper and lower production fluid inlets 160 and 162 of the lower pump section 124 are formed .in the upper and lower ends of the lower pump cylinder barrel 132, as shown in FIGS. 4 and 5, respectively, and respectively communicate with the upper and lower ends of the lower pump cylinder 128 through suitable upper and lower inlet check valve means 176 and 178 respectively carried by the lower intermediate sealing adapter 148 and the fitting 150.

The foregoing completes the description of the manner in which production iiuid from the well is admitted into the upper and lower ends of the upper and lower pump sections 122 and 124 and the manner in which the production fluid is discharged therefrom into themain outlet passage means 46 through the branch outlet passage means 44, S2 and 5S will now be described.

The upper intermediate sealing adapter Mais provided between the seals 98 and 164 thereon with ports forming a production fluid outlet 18! for the upper end of the upper pump section 122, this outlet registering with the branch outlet passage means 44 when the pump assembly 22 is in its operative position in the bottom hole assembly 20. As shown in FIG. 3 of the drawings, the upper intermediate sealing adapter 96 carries an outlet check valve means 182 through which production fluid discharged from the upper end of the upper pump cylinder 126 flows to the production fluid outlet 130 by way of suitable ports, passages, and the like in the sealing adapter in question, these being clearly shown in FG. 3 so that a further description is unnecessary. Similarly, the branch outlet passage means 44 with which the production fluid outlet 180 registers includes a collection of annular grooves, ports, and the like in the upper intermediate sealing collar 42 which are clearly shown in FIG. 3 so that a further description is not required.

Disposed between the seals 166 and 168 on the lower intermediate sealing adapter 148 is a production iiuid outlet 184 comprising circumferentially spaced ports formed in the sealing adapter 148 and registering with the branch outlet passage means 52 in the lower intermediate sealing collar 50 when the pump assembly 22 is in its operative position. As shown in FIG. 4 of the drawings, the branch outlet passage means 52 comprises ya collection of grooves, ports, and the like in the lower intermediate sealing collar 50 which it is unnecessary to describe specically. The production tluid outlet 184 serves the lower end of the upper pump section 122 and the upper end of the lower pump section 124, the production fluid outlet 184 communicating with the lower end of the upper pump cylinder 126 through an outlet check valve means 186 and communicating with the upper end of the lower pump cylinder 128 through an outlet check valve means 188, the two outlet check valve means just mentioned being carried by the lower intermediate sealing adapter 148. Communication between the lower end of the upper pump cylinder 126 and the production fluid outlet 134 through the outlet check valve means 186 and communication between the upper end of the lower pump cylinder 128 and the production liuid outlet 184 through the outlet check valve means 18S are established by suitable ports, passages, and the like in the lower intermediate sealing `adapter 148, these being clearly shown in FlG. 4 of the drawings so that a further description is not needed. Similarly, the branch outlet passage means 52 with which the production uid outlet 184 communicates when the pump assembly 22 is in its operative position is formed by suitable grooves, ports, and the like in the lower intermediate sealing collar 50 which are also clearly shown in FIG. 4 so that they need not be described in detail.

The lower end of the lower pump section 124 discharges production fluid through an outlet check valve means 190, FIG. 5, carried by the fitting 150, this fitting being provided with suitable ports, passages, and the like which, as shown in FIG. 5, connect the lower end of the lower pump cylinder 128 to the annular space between the balance tube 142 and the tube 152 which connects the fitting 150 to the lower sealing adapter 154. As shown in FIG. 6, the lower sealing adapter 154 is provided with suitable passages, ports, and the like which convey the production iluid discharged by the lower end of the lower pump section 124 to a production uid outlet 192 formed by circumferentially spaced ports in the lower sealing adapter below the seal 170. As FIG. 6 clearly shows, the production fluid discharged by the lower end of the lower pump section 124 flows downwardly around the inlet plug 68 and then through the branch outlet passage means 58 in the bottom shoe S6 into the main outlet passage means 46.

The pump assembly 22 is run into and out of the well hydraulically in the usual manner for pump assemblies ot' this type. Brieliy, the pump assembly 22 is run in from tne surface into its operative position in the bottom hole assembly 2t) by introducing fluid into the supply tubing 30 above the pump assembly at a pressure sufficient to move the pump assembly downwardly into its operative Iposition. To run the pump assembly 22 out, tluid is introduced into the upper end of the production tubing 34, whereby the iluid in the production tubing and in the main outlet passage means 46 enters the pump-assembly housing provided by the bottom hole assembly 20 below the pump assembly 22 by way of the branch outlet passage means 58 in the bottom shoe 56, as shown in FG. 6 of the drawings. Initially, upward pressure is applied to an annular area of the inlet plug 68 equal to the cross sectional area of the pump assembly 22 minus the area of engagement between the inlet plug 68 and the standing valve assembly 62. As soon as the pump assembly 22 unseats from the standing valve assembly 62, whereupon the standing valve closes, the upward pressure applied to the production tubing 34 acts on the entire cross sectional area of the pump assembly to move it upwardly. Until such time as the lowermost seal disengages the lower sealing collar 55, it prevents bypassing of the iluid introduced through the production tubing 34 past the pump assembly. Thereafter, the packer cups 82 at the upper end of the pump assembly 22 prevent bypassing so that the pump assembly is hydraulically lifted Ito the surface.

Considering one important feature of the present invention, each of the various external annular seals 90, 92, 98, 164, 166, 168 and 176 carried by the pump assembly 22 is loaded in the vertical or axial direction when the pump assembly is in its operative position to such an extent that it will not expand and contract excessively as the pressure of one or the other of the uids which it separates decreases and increases, respectively. In order to minimize such expansion and contraction of the seals in question, they are pressurized or loaded to an extent of at least the same order of magnitude as the differences between the pressures of the uids which they separate, and preferably higher. The resultant minimizing of expansion and contraction of each of the seals mentioned as the pressure of one or the other of the iluids separated thereby decreases and increases minimizes internal friction within the seal, and thus prevents the heat generation which such internal friction would produce, the net effect being a very marked increase in the service life of the seal. Without such loading or pressurization, the external seals on the pump assembly which separate fluids having variable pressure diiferentials therebetween would burn out in a very short period of time from the heat generated by internal friction as they expand and contract.

Further, since the foregoing loading or pressurization of each of the seals 90, 92, $8, 164, 166, 168 and 170 is in the axial direction, it results in squeezing such seal outwardly into sealing engagement with the corresponding component of the bottom hole assembly 20 only when the pump assembly 22 is in its operative position. Thus, it is not necessary to subject the seals in question to initial squeezes, which means that their external diameters are less than the external diameters of the sealing adapters of the pump assembly as the latter is run into or out of the well. Consequently, the external seals on the pump assembly cannot be abraded by the supply tubing 30 and the bottom hole assembly 20 as the pump assembly is run in or out, which is another important feature.

The various external seals 90, 92 98, 164, 166, 168 and 170 are pressurized or loaded in similar fashions so that it is necessary to consider how this is accomplished in connection with only a couple of thc seals, e.g., the seals 9S and 164, for purposes of illustration. The manners in which the seals 93 and 164 are pressurized when the pump assembly 22 is in its operative position are shown in FIGS. 10 and l1, respectively, these ligures duplicating portions of FIG. 3 on an enlarged scale.

Considering the seal 98 first, it encircles a reduced diameter portion 194 of the upper intermediate sealing adapter 96 and is engageable with a liner 196 forming part of the upper intermediate sealing collar 42. The seal 98 is disposed between a lower rigid sleeve 198, which encircles the reduced diameter portion 194 of the sealing adapter 96 and which is engageable with an annular shoulder 200 thereon, andan upper rigid, differential area sleeve 202 which is axially slidable on the reduced diameter portion 194 of the sealing adapter 96 and on a further reduced diameter portion 204 thereof, an O-ring 206 maintaining a fluid tight seal between the sleeve 202 and the portion 204 of the sealing adapter 96. The sleeve 202 has a small-area lower end 208 engageable with the seal 98 and a large-area upper end 210, this sleeve also having an internal annular surface 212 the area of which is equal to the difference between the cross sectional areas of the portions 194 and 204 of the sealing adapter 96, and thus to the difference between the areas of the upper and lower ends 210 and 208 of the sleeve.

The upper end 210 of the sleeve 202 is exposed to the pressure in the annular operating fluid passage 76 through the slight annular clearance, not shown, which is necessarily present between the motor cylinder barrel 101 and the liner 196 of the upper intermediate sealing collar 42, the pressure in the annular operating fluid passage 76 being alternately the operating fluid pressure in the supply tubing 30 and the spent operating fluid pressure in the return tubing 32. The annular surface 212 of the sleeve 202 is exposed to the production fluid inlet pressure through one or more ports and passages 214 and 216 in the upper intermediate sealing adapter 96, the passage or passages 216 communicating with the production fluid inlet 156 in the manner shown in FIG. 3 of the drawings.

It will b'e apparent from the foregoing that the sleeve 202 is a differential area sleeve having either the pressure of the operating lluid in the supply tubing 30, or the presysure of the spent operating fluid in the return tubing 312, applied to the upper end 210 thereof and having the much lower production fluid inlet pressure applied to the annu lar surface 212 thereof. The pressures acting on theV upper end 210 of the sleeve 202 and the pressure acting -on the 4annular surface 212 thereof produce an laxial force which axially compresses the seal 98 and which is equal :to the area of the -annular surface 212 multiplied by the difference between the production yfluid inlet pressure and either the pressure of t-he operating fluid in the supply tubing 30, or the pressure of the spent operating fluid in the return tubing 32. ln either event, the pressure applied to the seal 98 exceeds the difference between the .pressures which -this seal separates, the pressure below the seal 98 being the pressure of the production fluid column in the production tubing 34, and the pressure above this seal being either the pressure of the spent operating fluid column in the return tubing 32, which is the same as the pressure of the production fluid column in the production tubing if the densities of the operating and production fluids are the same, or the pressure o-f the operating fluid in the supply tubing 30. Consequently, as the pressure above the seal 98 alternates between the pressure in the supply tubing 30 and the pressure of the 4spent operating fluid column in the return tubing 32, the seal cannot expand and contract excessively and thus cannot generate excessive heat by internal friction so that its service life is materially extended, which is an important feature.

'Referring to FIG. ll of `the drawings, encircling the sealing adapter 96 is a band 220 which, in turn, is encircled by the seal 164, the latter being engageable with the liner 1196 of the sealing collar 42. The seal 164 is disposed between a sleeve 222, which encircles the band 220 and which is seated on 'the upper end of the upper pump cylinder barrel 224 slidably engaging the band 220 'and the sealing adapter 96. The sleeve 224 has a Asmall-area lower end l130, and a differential area sleeveV 10 226 engaging the seal 164 and a large-area upper end 228 exposed to the production fluid discharge pressure in the branch outlet passage means 44, this sleeve being sealed internally relative to the sealing adapter 96 by an O-iing 230. The differential area sleeve 224 is also provided with an internal annular surface 232 facing in the opposite direction from the upper end 228 thereof and having an area equal to the difference between the areas of the Iupper and lower ends 228 and 226. y As will be apparent, the band 220 effectively increases the diameter of a portion of the sealing adapter 96 to provide the differential area between the upper and lower ends 228 and 226 of the sleeve 224. t

As previously stated, the upper end 228 of the sleeve 224 is exposed to the production fluid outlet pressure in the branch outlet passage means 44. The annular surface 232 is exposed to the production fluid linlet pressure in the upper annular inlet passage 72, as will be apparent from FIG. 3, through clearances, not shown, inherently present .between the liner 196 and the upper pump cylinder barrel 130, between the upper pump cylinder barrel and the sleeve 222 and the band 220 and between the sealing adapter 96 and the band 200. Consequently, the .production fluid discharge pressure acting on the upper end 228 of the sleeve 224 and the production fluid inlet pressure acting on the annular surface 23-2 thereof result in lthe application of a pressure -to the seal 164 equal to the area of the annular surface 232 multiplied by the difference between the production fluid discharge pressure and the production fluid inlet pressure.` Thus, the seal 16'4 -is subjected to a pressure at least equal to the difference between the pressure-s of ythe fluids which it separates.

The seals 166, 168 and 170 are pressurized in much the same manner as the seal 164, utilizing the difference between the production fluid discharge pressure and the production fluid inlet pressure. Consequently, a further description is unnecessary.

The seal at the upper end of Ithe pump assembly 22 is pressurized in much lthe same manner as the seal 98, except that the difference between the operating fluid pressure in the supply tubing 30 and the pressure of the `spent operating fluid in the return tubing 32 is utilized, as will be apparent from FG. 2 of the drawings. Briefly, the seal 90 is pressurized by a differential area sleeve 234 having its upper end 236 exposed to the operating fluid pressure in the supply tubing 30 and having a smaller, downwardly facing annular surface 238 exposed to the return `fluid pressure in the operating lluid exhaust 88 through one or more ports and passages 240 and 242. The :action of the sleeve 234 on the seal 90 is very similar to that of the sleeve 202 on the seal 98 so that a funther description is not required. The pressure applied to the seal 90 by the sleeve 234 in this fashion is transmitted to the seal 92 mechanically by sleeves 244, 246 and 248 tsl-idable on the upper sealing adap-ter 86, the sleeve 246 having the operating fluid exhaust 88 formed therein.

Thus, when the pump assembly 22 is in its operative position and `is in operation, all olf the external seals thereon are pressurized to urge them int-o `sealing engagelment with the corresponding Vcomponents of the bottom hole assembly 20, and to prevent .them from expanding and contracting so that the resultant detrimental ellect olf heat generation due to internal `friction is avoided. Further, all of the seals which separate the clean operating Ifluid from the possibly contaminated production fluid, viz., tlievsealsV 98, 164, 166, 168 and 170, are pressurized when the pump assembly 22 is in its operative position with the standing valve 62 open, even if the pump is shut down; Thus, the operating fluid cannot become contaminated, which is animportant feature. When the pump assembly 22 is being run in or out, the external seals are retracted into the ggrooves `formed by the sleeves whichV receive ithem therebetween so that the seals i l cannot be abraded -by contact with the bottom hole asse-mbly 20, or the supply tubing 3G. i

Preferably, the annular seals 90, 92, 98, 164, 166, 168 and 170 have steel cores to insure outside diameter accuracy and to resist blowing out of their grooves.

Turning now to another important feature of the present invention, the main outlet passage means 46 paralleling the pump assembly 22 includes a pipe 250 interconnecting the upper and lower intermediate sealing collars 42 and 50 and a pipe 252 interconnecting the lower intermediate sealing collar t) and the bottom shoe 56. Interconnecting the upper and lower intermediate sealing collars 42 and 50 by means of the upper pump housing tube48 andthe pipe 250', and interconnecting the lower intermediate sealing collar 50 and the bottom shoe 56 by means of the lower pump housing tube 54 and the pipe 252, presents certain problems which are considered hereinafter and which the present invention overcomes in the manner set forth hereinafter. For convenience, the consideration of this aspect of the invention will be restricted to interconnecting the lower intermediate sealing collar 50 and the bottom shoe 56 with the lower pump housing tube 54 and the pipe 252, with the understanding that the discussion also applies to interconnecting other components of the bottom hole assembly 20.`

Referring to FIGS. 4, 5 and 6 of the drawings, it will be noted that the pump housing tube 54 is threaded into the lower sealing collar 55 by means of ordinary tapered pipe threads. Consequently, once the lower end of the pump housing tube 54 is threaded all the Way into the sealing collar 55, no further relative rotation of these parts is possible. However, it is necessary to provide relatively unrestricted rotation between the bottom shoe 56 and the sealing collar 50 at some point to permit alignment of the portions of the sealing collar 50 and the bottom shoe 56 into which the parallel pipe 252 is threaded in the manner shown in FIGS. 4 to 6 of the drawings, and to space the sealing collar 5t) and the bottom shoe accurately. For this purpose, the upper end of the pump housing 254 is threaded into the sealing collar 50 with extended, i.e., straight threads, and is secured by a lock nut 256, FIG. 4, threaded on the pump housing tube and seated against the sealing collar 50. With this construction the sealing collar 50 may be rotated relative to the pump housing tube 54 to align the portions of the sealing collar 5t) and the bottom shoe 56 into which the pipe 252 is threaded. Once this is done, the lock nut 256 is tightened to maintain the desired relative angular positions, and the desired axial spacing, of the sealing collar 50 and the bottom shoe 56.

As will be apparent, since relative rotation between the bottom shoe 56 and the sealing collar 50 must occur while the desired angular positions and axial spacing of these components are being established, connecting the parallel pipe 252 to the sealing collar 50 and the bottom shoe 56, or to at least one of them, must be done later. Also, there must be provision for axial movement of the pipe 252 relative to one or the other of the sealing collar 50 and the bottom shoe 56 to permit threaded connections of the pipe 252 to both of these components.

The present invention solves the foregoing problems by dividing the vpipe 252 into an upper section 258 and a lower section 260 with a telescoping connection or slip joint 262 theretbetween. Referring to FIG. 5 of the drawings, threaded onto the upper end of the lower pipe section 260 is a coupling 264 having a stem 266 which is slidable in the upper pipe section 25S and which carries an 0-ring 268 to provide a iiuid tight seal therebetween. A gland nut 276 is threaded onto the coupling 264 and is provided with an internal annular flange 272 engageable with an external annular flange 274 on the upper pipe section 258.

With the foregoing construction, after the sealing collar Si) and the bottom shoe 56 have been locked in their proper relative positions, the telescoping connection 262 is contracted sufficiently to permit threading the upper and lower pipe sections 25S and 260into the sealing collar 5t) and the bottom shoe 56, respectively, the telescopic connection extending as this is done. Alternatively, One of the pipe sections 253 and 260 is initially threaded into the corresponding components 50 or 56 of the bottom hole assembly 20 and the proper relative positions of the sealing collar 50 and the bottom shoe 56 are then established with the telescopic connection 262 contracted to permit the pipe section 258 to clear the sealing collar 50, or the pipe section 260 to clear the bottom shoe 56. Thereafter, if the pipe section 258 was initially threaded into the sealing collar 50, the pipe section 260 is threaded into the bottom shoe 56, the telescopic connection 262 extending as this is done. yIn either case, once the pipe sections 25S and 260 are tightly threaded into the sealing collar 5i) and the bottom shoe 56 by means of the tapered pipe threads shown, the gland nut 270 is tightened to complete the installation. Thus, the telescopic connection 262 between the pipe sections 253 and 260 provides a simple means of connecting the pipe 252 to the sealing collar 50 and the bottom shoe 56 after the relative positions of these components of the bottom hole assembly 20 have been established. Also, the gland nut 270 is tightened sufficiently to tension the pipe sections 258 and 260 to the extent necessary to prevent bowing of the pump housing tube 54 by the bending moment produced by the column pressure within the pipe 252 acting on the bottom shoe 56, which is an important feature.

Although exemplary embodiments of the present invention have been disclosed herein for purposes of illustration, it will be understood that various changes, modifications and substitutions may be incorporated in such embodiments without departing from the spirit of the inveiition as defined by the claims which follow.

We claim:

1. In a fluid operated well pump system which includes a bottom hole assembly having housing means for housing a fluid operated pump assembly and which includes high pressure and low pressure fluid sources, said housing means including a sealing collar and said pump assembly including a sealing adapter registrable wit-h said sealing collar'when said pump assembly is in an operative position in said housing means, the combination of:

(a) means providing an external annular shoulder on and encircling said sealing adapter;

(b) an elastomeric annular seal encircling said sealing adapter and engageable with said annular shoulder;

(c) said annular seal being engageable with the interior of said sealing collar when said pump assembly is in said operative position;

(d) a sleeve which encircles and is slidable axially of said sealing adapter and one end of which is engageable with said annular seal;

(e) the other end of said slee-ve being larger in cross sectional area than said one end thereof;

(f) said sleeve having an internal annular surface which faces in the same direction as said one end of said sleeve and the cross sectional area of which is equal to the difference between the cross sectional areas of said ends of said sleeve;

(g) means connecting said annular surface of said sleeve to said low pressure source when said pump assembly is in said operative position; and

(lz) means connecting said other end of said sleeve to said high pressure source when said pump assembly is in said operative position. l

2. In a reciprocating fluid operated pump system having a cylinder alternately subjected at each end to high pressure and low pressure, the combination of:

(a) a source of substantially constant high pressure;

(b) a source of substantially constant low pressure; i (c) packing means sealing the high and low pressures alternately applied to the ends of the cylinder; and

(d) means operable by the diiferential between said substantially constant high pressure and said substan- Y 13 tially constant low pressure for applying to said packing means a substantially constant pressure greater than the high and low pressures alternately appliedt-hereto.

3. In a duid operated Well pump system which includes a fluid operated pump assembly movable downwardly from the surface through a pump tubing into an operative position in a pump housing means provided by a bottom hole assembly connected to the lower end of said pump tubing, said pump assembly having external annular seal grooves therein, the combination of:

(a) elastomeric annular seals respectively disposed in said seal grooves and respectively having outside diameters which, when said seals are unstressed, are less than the outside diameters of said seal grooves;

(b) whereby said seals, when unstressed, are entirely within said seal gnooves so that said pump assembly may be moved between the surface and its operative position through said pump tubing without bringing said seals into contact with said pump tubing; and

(c) uid-pressure-diiferential-operated means for axial- `ly compressing said seals when said pump assembly is in its operative position so as to expand them radially outwardly into sealing engagement with said pump housing means.

4. A fluid operated well pump system as set forth in claim 3 wherein:

(a) said seals are subjected to fluctuating fluid pressure differentials when said pump assembly is in its operative position and is in operation therein; and wherein (b) said -uidpressure-differential-operated means includes means for producing in said seals pressures greater than the uctuat-ing ituid pressure differentials to which they are subjected when said pump assembly is in operation.

References Cited by the Examiner UNITED STATES PATENTS 1,333,342 3/20 Robertson etal 285--101 2,527,929 lO/ 50 Hebard 10S-225 2,533,097 12/50 Dale 285-302 2,712,458 7/55 Lipson 285-101 2,899,218 8/59 Creighton 285-302 LAURENCE V. EFNER, Primary Examiner'. ROBERT M. WALKER, Examiner. 

1. IN A FLUID OPERATED WELL PUMP SYSTEM WHICH INCLUDES A BOTTOM HOLE ASSEMBLY HAVING HOUSING MEANS FOR HOUSING A FLUID OPERATED PUMP ASSEMBLY AND WHICH INCLUDES HIGH PRESSURE AND LOW PRESSURE FLUID SOURCES, SAID HOUSING MEANS INCLUDING A SEALING COLLAR AND SAID PUMP ASSEMBLY INCLUDING A SEALING ADAPTER REGISTRABLE WITH SAID SEALING COLAR WHEN SAID PUMP ASSEMBLY IS IN AN OPERATIVE POSITION IN SAID HOUSING MEANS, THE COMBINATION OF: (A) MEANS PROVIDING AN EXTERNAL ANNULAR SHOULDER ON AND ENCIRCLING SAID SEALING ADAPTER; (B) AN ELASTOMERIC ANNULAR SEAL ENCIRCLING SAID SEALING ADAPTER AND ENGAGEABLE WITH SAID ANNULAR SHOULDER; (C) SAID ANNULAR SEAL BEING ENGAGEABLE WITH THE INTERIOR OF SAID SEALING COLLAR WHEN SAID PUMP ASSEMBLY IS IN SAID OPERATIVE POSITION; (D) A SLEEVE WHICH ENCIRCLES AND IS SLIDABLE AXIALLY OF SAID SEALING ADAPTER ONE END OF WHICH IS ENGAGEABLE WITH SAID ANNULAR SEAL; (E) THE OTHER END OF SAID SLEEVE BEING LARGER IN CROSS SECTIONAL AREA THAN SAID ONE END THEREOF; (F) SAID SLEEVE HAVING AN INTERNAL ANNULAR SURFACE WHICH FACES IN THE SAME DIRECTION AS SAID ONE END OF SAID SLEEVE AND THE CROSS SECTIONAL AREA OF WHICH IS EQUAL TO THE DIFFERENCE BETWEEN THE CROSS SECTIONAL AREAS OF SAID ENDS OF SAID SLEEVE; (G) MEANS CONNECTING SAID ANNULAR SURFACE OF SAID SLEEVE TO SAID LOW PRESSURE SOURCE WHEN SAID PUMP ASSEMBLY IS IN SAID OPERATIVE POSITION; AND (H) MEANS CONNECTING SAID OTHER END OF SAID SLEEVE TO SAID HIGH PRESSURE SOURCE WHEN SAID PUMP ASSEMBLY IS IN SAID OPERATIVE POSITION. 